1. Field of Invention
The present invention relates to retractable pens. More particularly, the present invention relates to retractable pens having felt tip, roller ball, fountain and other writing tips employing volatile writing fluids. Still more particularly, the present invention relates to retractable pens having self-sealing writing tip openings.
2. Description of Prior Art
Felt tip, roller ball, fountain and other writing tips using volatile inks offer many desirable writing features not found in conventional ball point pens. Pens using these writing tips, however, lack the convenience of easy writing tip retraction. Instead, pens using volatile inks generally must have a cap placed over their writing tips after each use. Failure to recap such pens whether through oversight or loss of the cap, usually results in permanent pen damage, i.e., their ink reservoirs dry out or solid components of their writing fluids dry out and become deposited in the writing tips impairing proper pen function.
Such pens must also be recapped in order to prevent soilage of clothing while such pens are being carried. Unlike ball point pens which use viscous inks, pens using volatile inks generally use low viscosity inks which can produce large clothing stains from capillary action.
Even ball pens using viscous inks tend to dry out over time. Thus there is an evident need for a retractable pen which provides a means for preventing pen damage due to ink drying, particularly in pens using volatile inks, but also in ball pens.